Directional climate control system with infrared targeting

ABSTRACT

A heating, ventilating, and air conditioning (HVAC) system has a steerable outlet for directing a stream of treated air into a passenger compartment of a vehicle. A thermographic imager is configured to capture thermographic images covering a fixed region within the passenger compartment in which an occupant is potentially located. The HVAC control circuit is configured to a) compress a thermographic image to a temperature map representing pixels of the thermographic image falling within a predetermined temperature range corresponding to the occupant, b) filter the temperature map according to a sliding window to coalesce continuous regions of pixels on average falling within the predetermined temperature range, c) quantify an area for each continuous region, d) locate a centroid of a continuous region having a largest area, and e) aim the steerable outlet toward the centroid.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a division of co-pending U.S. application Ser. No.14/492,637, filed Sep. 22, 2014, which is incorporated herein byreference.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH

Not Applicable.

BACKGROUND OF THE INVENTION

The present invention relates in general to automotive HVAC systems,and, more specifically, to automatic adjustment of steerable air outletsto direct treated air to optimize passenger comfort and reduce energyusage.

Heating, ventilating, and air conditioning (HVAC) systems control theclimate in transportation vehicles such as automobiles in order tomaintain thermal comfort of the vehicle occupants. Typically, a blowerpasses air through heat exchangers and delivers conditioned air tovarious points within the passenger cabin. Warm air may be provided by aheater core obtaining heat from coolant flowing in a combustion engine,for example. Cool air may be obtained using a compressormechanically-driven by the engine. Electrified vehicles such as hybridelectric vehicles (HEVs) and battery electric vehicles (BEVs) mayinstead use electrically powered devices such as PTC resistance heatersand electric air conditioning compressors.

The simplest climate control systems in motor vehicles provide theoccupant with direct control of the intensity of heating or cooling, theoperating speed of the blower, and the relative amount of air flow goingto different registers. This requires the user to continually monitorand adjust the climate control settings in order to remain comfortable.The vehicle occupants, however, may not understand how to best controlthe HVAC system to optimize efficiency. They may turn the control knobsto a maximum output while aiming the blower vanes upward or downwardaway from their bodies, sending the conditioned air tumbling onto lessimportant surfaces and requiring more energy to make the occupantscomfortable. This also results in greater blower fan noise than isreally necessary to achieve the desired thermal comfort.

Electronic automatic temperature control (EATC) systems have also beenintroduced wherein a feedback control system monitors ambient airtemperature within the passenger compartment and automatically adjustsblower speed and heater core or air conditioning operation to maintain adesired temperature setting. In some vehicles, multiple zones have beenimplemented with separate automatic temperature control with individualtarget temperature settings being made for each zone.

Traditional HVAC systems only indirectly control the actual skintemperature of an occupant. Because skin temperature is a betterindicator of actual occupant comfort, systems have been investigated forregulating HVAC system operation using infrared (IR) sensors todetermine the skin temperature of the vehicle occupants and thenadjusting a temperature setpoint of the HVAC system in the directionrequired to achieve a target skin temperature. However, thethermodynamic environment in a vehicle interior is complex, as are therelationships between various HVAC control settings and the resultingeffect on skin temperature of different occupants. Therefore, previoussystems have been relatively complex and not cost effective.

In order to reduce energy consumption and to provide optimal comfort,various systems have also been proposed which automatically adjust thepattern of air flow delivered into the passenger compartment based uponseat occupancy (e.g., turning off vents where a seat is unoccupied).However, no known system has provided sufficient accuracy or performanceto truly optimize directional adjustment of treated air over asufficiently wide range of thermal conditions.

SUMMARY OF THE INVENTION

The present invention uses thermographic image processing to identifyoccupants'skin surfaces which can be targeted with a treated air streamusing electronically-controlled vents which have two-axis directionalcontrol, and optionally have a nozzle control for focusing the airstream. Based on detected seat occupancy, airflow from multiple ventsmay be targeted at detected skin targets according to which seats areoccupied. Thermographic images can be taken successively in order toupdate air stream direction and flow rate under changing conditions.

In one aspect of the invention, a vehicle apparatus includes a heating,ventilating, and air conditioning (HVAC) system having a steerableoutlet for directing a stream of treated air into a passengercompartment of a vehicle. A thermographic imager is configured tocapture thermographic images covering a fixed region within thepassenger compartment in which an occupant is potentially located. TheHVAC control circuit is configured to a) compress a thermographic imageto a temperature map representing pixels of the thermographic imagefalling within a predetermined temperature range corresponding to theoccupant, b) filter the temperature map according to a sliding window tocoalesce continuous regions of pixels on average falling within thepredetermined temperature range, c) quantify an area for each continuousregion, d) locate a centroid of a continuous region having a largestarea, and e) aim the steerable outlet toward the centroid.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an automotive passenger compartmentincluding an HVAC system with multiple, steerable air outlets or ventsfor providing climate control for occupants of the vehicle.

FIG. 2 is a block diagram showing one preferred embodiment of a vehicleapparatus of the invention.

FIGS. 3 and 4 are side views of steerable air outlets.

FIG. 5 shows a sequence of image data used in a preferred embodiment foraiming a steerable air outlet toward an occupant.

FIG. 6 is a flowchart of one preferred embodiment of a method for aiminga steerable air outlet.

FIG. 7 is a flowchart of one preferred embodiment for determining targetareas.

FIGS. 8 and 9 are representative plots showing predetermined temperatureranges for identifying an occupant in a thermographic image.

FIG. 10 shows an array of pixels for a portion of a thermographic imageafter conversion to a bi-valued temperature map.

FIGS. 11 and 12 illustrate a sliding window at successive positionsduring filtering of a temperature map to coalesce regions within thebi-valued temperature map.

FIG. 13 illustrates an array of pixels after coalescing the regions.

FIG. 14 illustrates one preferred technique for locating a centroidwithin a coalesced region.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

FIG. 1 shows a passenger compartment 10 of an automotive vehicle withvarious seating locations such as a front seat 11 and rear seats 12. Avehicle HVAC system includes a plurality of air outlets or vents 13-17for directing respective streams of treated air into passengercompartment 10. One or more of vents 13-17 has a steerable outlet sothat the direction and/or focus (i.e., spread) are automaticallyadjustable by the HVAC system.

FIG. 2 shows an HVAC system 20 with various components interconnected byan electrical system 21 preferably including an electrical wiringharness and a multiplex communication system as commonly used in theindustry. An HVAC control circuit 22 may preferably be comprised of atypical electronic module including customized circuits and/or one ormore programmable microcontrollers with appropriate software and/orfirmware as commonly deployed in automotive vehicles.

A thermographic imager, preferably taking the form of an infrared camera23, is disposed at a forward location in the passenger compartment inorder to capture thermographic images covering a fixed region in andaround front seating areas 25 and 26. Occupant seating area 26 may beprovided for a driver, for example. HVAC controller may be configured toalways assume that a driver is present. On the other hand, occupantseating 25 may represent a passenger seat in which an occupant ispotentially located but may also be unoccupied. Another infrared camera24 may be disposed in a rearward location in order to capturethermographic images covering a rear seat area in the passengercompartment including occupant areas 27 and 28.

In the front seat area, blowers 30 and 37 for right and left sides ofthe passenger compartment may be provided which are separatelycontrollable with a variable speed determined by HVAC controller 22.Blower 30 provides a stream of treated air to controlled register vents31, 33, and 35. Vent 31 is dash-mounted on a left, outer side of thedashboard near occupant seat 25 for providing an air stream 32. Vent 33is dash-mounted at a left, inside location to supplying an airstream 34,and vent 35 is a left floor vent for providing an airstream 36. At leastone of vents 31, 33, and 35 is automatically steerable to direct anairstream at a desired target within occupant area 25. Similarly,variable-speed blower 37 is coupled to dash-mounted front, inner, rightvent 38 supplying an airstream 39, front, outer, right vent 40 supplyingairstream 41, and right floor vent 42 supplying airstream 43 to occupantarea 26. In the present invention, any combination of steerable andfixed vents can be employed. Moreover, a particular controlled vent canalso be configured to direct an air stream alternately at different onesof the occupant areas.

A blower 44 also controlled by HVAC controller 22 supplies treated airstreams to rear vents 45, 47, and 49 directing airstreams 46, 48, and 50to occupant areas 27 and 28 as shown.

HVAC controller 22 is connected to or may include a lookup table 51 forpurposes described in detail below. In addition, HVAC controller 22 isconnected to various sensors including an ambient outside airtemperature sensor 52, a cabin internal air temperature sensor 53, andseat occupancy sensors 55. HVAC controller 22 is connected to acabin-mounted human machine interface (HMI) 54 as known in the art. Thecontrolled vents include actuators that are activated by HVAC controller22 based on signals from HMI 54, sensors 52, 53, and 55, and IR cameras23 and/or 24 in order to direct treated air to obtain passenger comfortat an optimized energy usage.

FIG. 3 shows one example of a steerable air outlet vent 60 installed inan instrument panel or dashboard 61. An air duct 62 receiving treatedair from a blower supplies the air to a movable outer vent shell 63retained upon a cup-shaped base 64. A gimbal mounting 65 that can berotated along one or more axes by a motor 66 under control of the HVACcontroller is connected to shell 63. By manipulating gimbal mount 65, anair stream exits an opening in shell 63 to move in a desired direction.Internal flaps or gates, such as a flap 67, may be disposed within shell63 and coupled with an actuator motor 68 in order to shape (i.e.,throttle) the edges of an exiting air stream in order to provide adesired focus of the outlet airstream.

FIG. 4 shows an alternative embodiment for steering an outlet airstreamwith a vent having controllable vanes 70 and 71. Although two vanes areshown, a greater number of vanes would normally be employed. Each vane70 and 71 has end pivot points 72 rotatably mounted to a vent housing(not shown). The vanes are all interconnected by a linking rod 73 tomaintain a parallel spacing. The up and down motion of rod 73 rotatesvanes 70 and 71 in concert in order to direct an outlet air stream alonga controllable direction. Rod 73 may be connected to an actuator motor(not shown) which is driven by the HVAC controller.

FIG. 5 depicts an overall process of the present invention for using athermographic image to identify a target location for aiming an outletair stream. A thermographic image 75 is captured according to a fixedfield of view using an infrared camera to return to multi-valued imagewith pixels having a color or intensity representing respectivetemperature values. Based on a predetermined temperature range selectedto include an expected temperature of exposed skin taking intoconsideration the ambient temperature conditions, the multi-valuedthermographic image is compressed to a bi-valued image 76 such thatpixels falling within the predetermined range are colored white and allother pixels are colored black, for example. Thus, image 76 comprises atemperature map in which regions of white pixels correspond to exposedareas of skin of a vehicle occupant. In the example shown, a head region81 and arm/hands regions 82 and 83 are discernible in temperature map76. However, imaging noise causes regions 81 to 83 to contain scatteredblack pixels making the region harder to detect automatically by thecontroller.

Image 77 comprises a further processed image in which regions of thepixels falling within the predetermined temperature range have beencoalesced so that the regions become substantially continuous with welldefined borders and no scattering of black pixels within the regions. Asdescribed below, coalescing may be performed by filtering using asliding window to successively re-assign each pixel value to match amajority of the respective surrounding pixels. Since the number ofidentified regions may exceed the number of steerable air outlets, thedetected regions may be ranked according to size to allow the largest tobe selected for targeting as shown in image 78. In an image 79, acentroid 88 of each selected continuous region is located in order toprovide a precise target for steering the corresponding air outlet.

A preferred method of the invention is shown in FIG. 6 wherein outsideambient temperature and internal cabin temperature are measured in step90. Preferably, performance of the method may be initiated by unlockingor opening a door to indicate that a driving cycle of the vehicle isabout to begin. In step 91, an initial thermographic image is captured,e.g., prior to any occupant being seated inside the passenger cabin. Theinitial image allows any particularly prominent infrared “hotspots” tobe recorded and identified. In step 92, the HVAC system is activated inresponse to initial conditions as identified by the temperaturemeasurements from step 90 and the initial IR image from step 91. Inaddition, the initial activation of the HVAC system may be based onhistorical HVAC settings for a temperature setpoint and blower speedthat were set by the driver for similar conditions on previous trips, oraccording to default control values designed by the manufacturer. Thetime for activating the HVAC may be determined in the conventionalmanner, such as when a vehicle engine is remotely started via a wirelesscontroller or when the driver enters the vehicle and starts the engineor other power plant using an ignition key, for example.

In response to a key-on, a thermographic image is captured in step 93with the driver seating in the corresponding position. The image in step93 may potentially contain additional occupants who will be present forthe impending drive cycle. Using the captured thermographic image,target areas are determined in step 94. The direction and/or focus ofvarious HVAC air stream outlets are adjusted in step 95. Optionally, theoutlet temperature of the HVAC system and the blower speed or intensitymay also be adjusted. After a predetermined period of time zit, a newthermographic image may be captured in step 96. Since the HVAC system isactively affecting the temperature environment when subsequentthermographic images are captured, the desired skin features may bemasked in the image by the appearance of the air stream. This effect isespecially present when the blower is operating at higher speeds. Inorder to reduce the presence of a temperature signature of the treatedair in the image, a check is performed in step 97 to determine whetherthe blower fan speed is above a threshold. If not, then target areas aredetermined in the subsequent image in step 94 and then the HVAC outputsare adjusted in step 95. If the fan speed is above the threshold, thenthe subsequent thermographic image can be filtered in step 98 to removethe effects of the treated air flow in the image. Filtering can beperformed based on the turbulent nature of an airflow as seen in atypical thermographic image (e.g., image regions with a certain texturecan be deleted from the image). Alternatively, the fan speed can betemporarily reduced or turned off completely during the capturing of thethermographic image.

FIG. 7 shows a preferred method for determining target areas in greaterdetail. In step 100, the measured internal and external ambienttemperatures are used to select the predetermined temperature range foridentifying regions in the image showing an occupant's skin. Theexternal temperature indicates whether the occupant's skin is beingraised or lowered from a normal body temperature by external conditions.The internal cabin temperature helps identify the expected temperaturesof interior surfaces within the vehicle (e.g., headrests). Thepredetermined temperature range is determined empirically in order toinclude expected skin temperatures while excluding as many of theinterior vehicle surfaces as possible. Preferably, values for thepredetermined ranges are stored in a lookup table within or accessibleto the HVAC control circuit.

The lookup may be organized according to index values for the internaland external temperatures. FIG. 8 shows one example for specifying atemperature range corresponding to one particular external temperatureand showing the changing range for varying internal temperature. Thepredetermined range has a maximum value defined by a curve 107 and aminimum value defined by a curve 108. For an internal temperature 112 atthe low end of curves 107 and 108, a predetermined range 110 is definedby the respective values of curves 17 and 108. For other values ofinternal temperature (at the same external temperature), a differentpredetermined range may be obtained such as range 111 at a higherinternal temperature indicated at 113. FIG. 8 is representative ofcurves that ar obtained for high external ambient temperatures (i.e., insituations calling for HVAC cooling). During hot external conditions,the interior of the vehicle is typically heated significantly, therebymaking it easier to distinguish skin temperatures. Therefore, thepredetermined range may be wider at range 111 than at range 110. At moremoderate temperatures, it may be more difficult to distinguish skintemperature from body structures, therefore requiring a narrower rangeat 110.

FIG. 9 is representative of colder external temperatures (i.e., asituation calling for heating of the passenger compartment) with curves114 and 115 defining the maximum and minimum temperatures of thepredetermined temperature range, respectively. Once again, at moreextreme (colder) temperatures it may be easier to distinguish theoccupant's skin in the image, so a wider predetermined range isspecified. At more moderate temperatures it again becomes harder todistinguish the occupants skin and the predetermined range is narrower.

Returning to FIG. 7, using the predetermined range the thermographicimage is compressed (i.e., converted) to a temperature map which assignsa first pixel value (e.g., a binary “1” for white) to each pixel fallingwithin the predetermined temperature range and assigning a second pixelvalue (e.g., a binary “0” for black) if it corresponds to a temperatureoutside the predetermined range. A portion of the bi-valued temperaturemap is shown in FIG. 10. Shaded squares 120 correspond to black pixelsin the temperature map outside the predetermined temperature range andunshaded squares 121 correspond to white pixels in the thermographicimage falling within the predetermined range which indicate a potentialtarget.

The following code written for Matlab demonstrates the compression of athermograph image into a black and white temperature map and displayingthe resulting image.

  %Find target areas: tol = 90; div = 30; r=252; g=243; b=102; img2a =img(:,:,1); img2b = img(:,:,2); img2c = img(:,:,3); idx1 =find(img2a>max(0,r-tol) & img2a<min(255,r+tol)); idx2 =find(img2b>max(0,g-tol) & img2b<min(255,g+tol)); idx3 =find(img2c>max(0,b-tol) & img2c<min(255,b+tol)); idx =intersect(idx1,intersect(idx2,idx3)); img2a = zeros(size(img2a)); img2b= zeros(size(img2b)); img2c = zeros(size(img2c)); img2a(idx) = 255;img2b(idx) = 255; img2c(idx) = 255; img2 = (img2a*0.2989 +img2b*0.5870 + img2c*0.1140); ax(2)=subplot(1,5,2); imshow(img2/255)%-------------

In step 102 of FIG. 7, potential target regions are coalesced byfiltering with a sliding window. As shown in FIG. 11, the sliding windowis preferably comprised of a pixel array 122 centered on a pixel 123.During the filtering process, window 122 is scanned over thethermographic image at each potential center pixel, with the value foreach center pixel being reassigned a new value in a coalesced image suchthat its new value matches a majority value for the pixels of thetemperature map within the sliding window at that position. At theposition shown in FIG. 11, for example, center pixel 123 would beassigned a binary value of 0 since most pixels within window 122 areblack. Stated in an equivalent manner, the average value for all thepixels within window 122 is determined (e.g., counting the white pixelsand dividing by the number of pixels covered by the window), with theresulting average being rounded to 0 or 1 to determine the value to beassigned to center pixel 123. FIG. 13 shows the coalesced image, withpixel 123 remaining black.

FIG. 12 shows a subsequent position for sliding window 122 centered onthe next pixel 124 in the same row. Since the majority of pixels boundedby this new position of sliding window 122 are black, pixel 124 remainsblack in the coalesced image of FIG. 13. When sliding window 122 movesto the next position in the same role, a pixel 125 is evaluated, and inthe example shown the majority value continues to be black. Therefore,pixel 125 switches to a value of 0 (i.e., white) in FIG. 13.

Thus, the filtering results in some minor adjustment of the actualborders of a potential target region. On the other hand, when it comesto isolated black pixels within a target region such as pixels 126 and127, the filtering by sliding window 122 reassigns them to a value of 1based upon the majority of pixels in the temperature map around thembeing white. Thus, FIG. 13 shows a coalesced image in which a morecontinuous target region based on the use of a sliding window to set allpixels to white whenever the value of the pixels within the window fallon average within the predetermined temperature range.

The following Matlab code continues the example to demonstrate thesliding window filtering to coalesce the target regions.

  %Coalesce patches to simplify: sq=20; %pad img2 w/ zeros around borderimg3=img2; img3=[zeros(sq,size(img3,2)); img3; zeros(sq,size(img3,2))];img3=[zeros(size(img3,1),sq) img3 zeros(size(img3,1),sq)]; for i = sq+1: size(img3,1)-sq  for j = sq+1 : size(img3,2)-sq   img3(i,j) =mean(mean(img3(i-sq:i+sq,j-sq:j+sq))); %  img3(i,j) = 200;  end  disp(i)end img3 = img3(sq:end-sq-1,sq:end-sq-1); %remove paddingimg3(img3>100)=255; img3(img3<=100)=0; ax(3)=subplot(1,5,3);imshow(img3/255) %-------------

The sliding window is comprised of a square array of pixels having asize adapted to provide the best performance for removing extraneousnoise while preserving the borders of target regions. An array size of20×20 pixels has been found to be effective. Since the sliding windowcannot be centered on a range of pixels along the outer edges of thethermographic image, the corresponding pixels may be disregarded informing the temperature map (or extra pixels with a zero value can beappended around the original image to facilitate placement of thesliding window.

Returning to FIG. 7, an optional determination of seat occupancy is madein step 103 in the event that there are air outlets capable of beingallocated between different seating locations and depending upon thepresence or absence of occupants in the corresponding locations. Step103 can be skipped if the steerable outlet(s) are only capable of beingaimed at one particular seat location. The determination of seatoccupancy can assist in determining how many air outlets will be aimedat each particular seating location, but such determination canalternatively be a fixed relationship or may be determined by othermeasures, such as by manual configuration using the HVAC HMI.

In step 104, coalesced regions are ranked by area. If there is only onesteerable air outlet then the ranking merely needs to identify thelargest coalesced region. Where there are multiple steerable outletsthat are going to be used to provide airflow to a particular occupant,then the ranking identifies the corresponding number of the largestcoalesced regions in order to assign each respective steerable outlet toa selected area. For example, in a vehicle with two steerable airoutlets for serving the front seat passengers and with only two frontseating positions (i.e., driver and passenger), then if no passenger ispresent the two largest coalesced regions in the driver's seatinglocation would be identified and targeted. On the other hand, if apassenger is present then the largest coalesced region for each of theseating locations are identified and the respective steerable outletsare aimed accordingly.

Ranking the regions by area involves summing the number of white pixelsin the region. The Matlab demonstration uses a function calledbwboundary in summing the areas as follows.

  %Rank area by size: [B,L] = bwboundaries(img3,′noholes′); for k =1:length(B)  area(k,1) = polyarea(B{k}(:,1),B{k}(:,2)); end area_sort =flipud(sortrows([area [1:length(B)]′],1)); ax(4)=subplot(1,5,4);which_areas = [1 ]; %specify ranks 1-to-N to target for i=which_areas L_temp = L;  L_temp(L_temp~=int16(area_sort(i,2))) = 0; L_ranked(:,:,i) = L_temp; end img4 = label2rgb(sum(L_ranked,3),@spring, [0.0 0.0 0.0]); imshow(img4) %-------------

In step 105, the centroids for the largest ranked region(s) to betargeted are determined. Then the outlets are aimed at the centroids instep 106. A preferred method for locating centroids is illustrated inFIG. 14. In a coalesced image 130, a coalesced region 131 has beenranked and identified as a target area (i.e., it corresponds to theoccupant's skin surface). A centroid 132 of region 131 may preferably bedetermined by calculating an average of the orthogonal coordinates ofthe pixels within the region 131. Thus, orthogonal coordinates x and ycorrespond to the columns and rows of image 130. The coordinates for twoof the included pixels are shown as (x₁, y₁) and (x₂, y₂). The x and yvalues for all the pixels within region 131 are averaged in order todetermine the average coordinate for centroid 132 (with the averagevalue being rounded off).

Continuing the Matlab example, locating the centroid is demonstrated asfollows.

  %Find centroids of target area(s): for i=which_areas  [row,col] =find(L_ranked(:,:,i)>0);  L_ranked_cent(i,:) = [round(mean(col))round(mean(row))]; end ax(5)=subplot(1,5,5); imshow(img4) hold onplot(L_ranked_cent(:,1),L_ranked_cent(:,2),′w.′,′markersize′,40)plot(L_ranked_cent(:,1),L_ranked_cent(:,2),′r.′,′markersize′,35)plot(L_ranked_cent(:,1),L_ranked_cent(:,2),′w+′,′markersize′,10)linkaxes(ax,′x′) % hold on % for k = 1:length(B) % boundary = B{k}; %plot(boundary(:,2), boundary(:,1), ′w′, ′LineWidth′, 2) % end

What is claimed is:
 1. A method of controlling a heating, ventilating,and air conditioning (HVAC) system having a steerable outlet fordirecting a stream of treated air into a passenger compartment of avehicle, comprising the steps of; capturing thermographic imagescovering a fixed region within the passenger compartment in which anoccupant is potentially located; compressing a thermographic image to atemperature map representing pixels of the thermographic image fallingwithin a predetermined temperature range corresponding to the occupant;filtering the temperature map according to a sliding window to coalescecontinuous regions of pixels on average falling within the predeterminedtemperature range; quantifying an area for each continuous region;locating a centroid of a continuous region having a largest area; andaiming the steerable outlet toward the centroid.
 2. The method of claim1 further comprising the steps of: measuring an external temperatureoutside the vehicle; measuring an internal temperature inside thecompartment; and selecting the predetermined temperature range inresponse to the external and internal temperatures.
 3. The method ofclaim 2 wherein the selecting step accesses a lookup table defining aminimum temperature and a maximum temperature of the predetermined rangeaccording to the measured internal and external temperatures.
 4. Themethod of claim 1 wherein the temperature map is comprised of pixelseach having either a first value indicating a temperature within thepredetermined range or a second value indicating a temperature outsidethe predetermined range, and wherein the sliding window of the filteringstep is comprised of a square array of pixels successively scanning thetemperature map, wherein a pixel at successive centers of the squarearray is assigned a value matching a majority value for the pixels ofthe temperature map within the square array at each successive position.5. The method of claim 1 wherein the centroid is located in response toan average of orthogonal coordinates of the pixels of the respectiveregion.
 6. The method of claim 1 wherein the HVAC system includes avariable speed blower, the method further comprising the step of:reducing an operating speed of the blower during the capturing step. 7.The method of claim 1 wherein the steerable outlet has a variable focus,the method further comprising the step of: adjusting the controllablefocus in proportion to a magnitude of the largest area from thequantifying step.
 8. The method of claim 1 wherein the HVAC systemincludes a plurality of steerable outlets serving an occupant, themethod further comprising the steps of: ranking a plurality ofcontinuous regions according to their respective quantified areas; andaiming each respective steerable outlet to a respective centroid of adifferent one of the ranked regions.
 9. The method of claim 1 whereinthe vehicle includes a seat occupancy detector and wherein the HVACsystem includes a plurality of steerable outlets, the method furthercomprising the step of: determining whether each one of a plurality ofseating positions within the passenger compartment are occupied; whereinone of the steerable outlets is primarily dedicated to a first one ofthe seating positions and is steered to a second one of the seatingpositions when the seat occupancy detector indicates that the first oneof the seating positions is unoccupied.